The control of the hydroxypropyl cellulose (HPC) substrate surface and its influence on the surface graft-modification of HPC was studied. In the modification process toluene-2,4-di-isocyanate (TDI), with the active bifunctional group, was used as a bridge. The paraisocyanate groups reacted with the hydroxyls of HPC substrate at first, while most orthoisocyanate groups still survived and can react with acrylic acid in the next procedure. The HPC substrate was modified by poly (acrylic acid) when the acrylic acid on the substrate participated in polymerization in acrylic acid solution. It was found that HPC substrates made from different polarity media led to different composition of hydroxy group on the HPC surface, and consequently affected the grafting reaction greatly. FT-IR spectra and TOF-SIMS proved that the reaction of the surface grafting by toluene-2, 4-di- isocyanate TDI molecules modified the substrate as a result of carboxyl groups or polyacrylic acid grafted onto the surface.

Key words: CELLULOSE, GRAFT COPOLUMERIZATION, TIME-OFF FLIGHT MASS SPECTROMETRY, ISOCYANATE P, POLYACRYLIC ACID